Sirexspecies (Hymenoptera: Siricidae) and their parasitoids inPinus sylvestrisin eastern North America

Siricids and their parasitoids were reared from Scots pine (Pinus sylvestrisL. (Pinaceae)) trees infested bySirex noctilioF. in central New York State.Sirex noctilioaccounted for 94.3% of the siricid specimens emerging, totaling 1313 specimens from six trees, with a maximum of 495 from one tree. Of the individuals emerging per tree, 20.6 ± 5.2% were female. Two native siricids,Sirex nigricornisF. andS. edwardsiiBrullè, also emerged from trees but in low numbers. Three hymenopteran parasitoid species that attack siricids emerged, totaling 21.8 ± 6.4% parasitism per tree.Ibalia leucospoides ensigerNorton (Ibaliidae) was by far the most abundant parasitoid, at 20.5 ± 6.3% parasitism per tree. The percentage of femaleS. noctilioemerging was positively correlated with wood diameter, whereas percent parasitism byI. l. ensigerwas negatively correlated with wood diameter.